package test

import (
	"fmt"
	"reflect"
	"testing"
)

//实现:使用反射调用方法,使用场景rpc服务调用

type FuncInfo struct {
	Name   string
	In     []reflect.Type
	Out    []reflect.Type
	Result []any
}

type TestUser struct {
	Name string
}

func (u *TestUser) GenerateUserName(firstName, lastName string) (string, error) {
	return fmt.Sprintf("%s-%s", firstName, lastName), nil
}

func TestReflectMethod(t *testing.T) {
	var u *TestUser
	typ := reflect.TypeOf(u)
	numMethod := typ.NumMethod()
	results := make(map[string]*FuncInfo, numMethod)
	for i := 0; i < numMethod; i++ {
		method := typ.Method(i)
		methodTyp := method.Type

		inNum := methodTyp.NumIn()

		ps := make([]reflect.Value, 0, inNum)
		in := make([]reflect.Type, 0, inNum)

		// 第一个参数永远是接收器，类似this的概念
		ps = append(ps, reflect.ValueOf(u))
		for j := 0; j < inNum; j++ {
			inTyp := methodTyp.In(j)
			in = append(in, inTyp)
			if j > 0 {
				ps = append(ps, reflect.Zero(inTyp))
			}
		}

		ret := method.Func.Call(ps)
		outNum := methodTyp.NumOut()
		out := make([]reflect.Type, 0, outNum)
		res := make([]any, 0, outNum)
		for k := 0; k < outNum; k++ {
			outTyp := methodTyp.Out(k)
			out = append(out, outTyp)
			res = append(res, ret[k].Interface())
		}
		results[method.Name] = &FuncInfo{
			Name:   method.Name,
			In:     in,
			Out:    out,
			Result: res,
		}
	}
	fmt.Println(results)
}